1. Technical Field
Embodiments of the subject matter disclosed herein generally relate to methods and systems usable for transmitting information along a pipe using specks.
2. Discussion of the Background
Oil and gas extraction remains a critical component of the world economy in spite of increasing challenges regarding accessibility of the oil reserves and safety of the exploitation. Oil and gas wells are bored deeper into the Earth's crust, often underneath the ocean or sea floor. To make a new well, rotating drill strings with a bit attached dig holes having diameters between 0.1 to 1 m. As the well is drilled, a casing may be inserted and cemented to the well's walls. A pipe made of pipe sections may be assembled inside the casing to form a continuous pipe inside the well.
At various location and at a bottom of a well drilled to extract oil and gas, as shown in FIG. 1, at hundreds or thousands of meters inside the Earth's crust, a plurality of sensors and tools 10 may acquire information about drilling parameters (e.g., inclination, temperature, pressure, weight of penetration, weight on bit) or rock formation (e.g., electrical conductivity, density, porosity, permeability).
Conventionally, the information (i.e., data) is transmitted from the sensors and tools to a server 20 at the surface, using a data cable 30 attached to a segmented pipe 40. The data cable 30 may be inside the pipe 40 or between the pipe 40 and the casing or the walls of the well. Alternatively, a wire is placed into a hole drilled in the wall of each drill pipe segment, and toroidal inductors are located at the top and at the bottom of each drill pipe segment. These inductors come into close proximity when the drill pipe segments are assembled, acting like a transmitting antenna or a receiving antenna, respectively.
The segmented pipe 40 is gradually built by adding on top segments (e.g., of about 9 m length) as the depth of the well increases. Parallel with increasing the length of the pipe 40, new segments are added to the data cable 30, including amplifiers, repeaters and other nodes 50 aimed to preserve the data quality along the path from the source (i.e., the sensors and tools 10 at the bottom of the well) to the destination (i.e., the server 20 at the surface).
As a person of skill in the art understands, the continuity and integrity of the data cable 30 are necessary for the data to reach the destination. However, the data cable 30 may broke and repairs are expensive and may take a long time. If the data cable 30 includes the wires inside the wall of the drill pipe segments, the drill pipe may have to be removed from the well.
Another method of communication between sensors and tools in the well and the surface is mud pulse telemetry, but this method offers a slow data rate (maximum 12 bits/s).
Accordingly, it would be desirable to provide systems and methods that have a good data rate transmission, are fault tolerant and cheap to repair if necessary.